Related by context. Frequent words. (Click for all words.) 58 reflectors 58 photocell 57 interferometers 56 optical wavelengths 55 eyepieces 55 photometer 53 loupe 53 redshifts 53 reflector 53 collimator 53 ultrasonic sensors 53 eyepiece 52 windings 52 magnetars 51 crystal oscillator 51 photometric 51 electromagnets 51 lenses 51 photodiode 51 spatial dimensions 50 frequency comb 50 voltmeter 50 shorter wavelengths 50 dye molecules 50 magnifications 50 photodiodes 50 baseplate 50 wavefront 50 emissivity 50 Type Ia supernovae 50 fluorescing 50 aperture 49 planet orbits 49 photonic crystal 49 parallax 49 photonic crystals 49 particle accelerators 49 crystals 49 LED headlamps 49 tach 49 spectrographs 49 haloes 49 chromophores 49 atoms 49 fluorescent tube 49 Fresnel lens 49 diodes 49 photometry 49 scanning tunneling microscope 49 LEDs 49 thermocouples 49 incandescent lamp 49 optical microscopes 49 magneto 49 electron spins 49 photodetector 49 parallax barrier 49 excitons 48 solenoid 48 electromagnet 48 lasers 48 pushbuttons 48 servo motors 48 magnifying lens 48 ON OFF 48 Accelerometers 48 Hawking radiation 48 magnification 48 TFTs 48 absorbance 48 starbursts 48 halogen lights 48 shutter glasses 48 filaments 48 nebulae 48 fluorophores 48 magnetic fields 48 magnetic flux 48 wavelengths 48 RGB LED 48 visible wavelengths 48 dimmer switches 48 Cepheids 48 LED headlights 48 apertures 48 Crab Nebula 48 toroidal 48 rev counter 48 QDs 47 spectra 47 phosphors 47 headlamps 47 spectrophotometers 47 fluorescent lamp 47 telescope 47 optical telescopes 47 prisms 47 optics 47 interferometry 47 photons 47 pulsed laser